path: root/include/linux/crypto.h

/*
 * Scatterlist Cryptographic API.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
 * and Nettle, by Niels Möller.
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option) 
 * any later version.
 *
 */
#ifndef _LINUX_CRYPTO_H
#define _LINUX_CRYPTO_H

#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/bug.h>
#include <linux/slab.h>
#include <linux/string.h>

/*
 * Autoloaded crypto modules should only use a prefixed name to avoid allowing
 * arbitrary modules to be loaded. Loading from userspace may still need the
 * unprefixed names, so retains those aliases as well.
 * This uses __MODULE_INFO directly instead of MODULE_ALIAS because pre-4.3
 * gcc (e.g. avr32 toolchain) uses __LINE__ for uniqueness, and this macro
 * expands twice on the same line. Instead, use a separate base name for the
 * alias.
 */
#define MODULE_ALIAS_CRYPTO(name)	\
		__MODULE_INFO(alias, alias_userspace, name);	\
		__MODULE_INFO(alias, alias_crypto, "crypto-" name)

/*
 * Algorithm masks and types.
 */
#define CRYPTO_ALG_TYPE_MASK		0x0000000f
#define CRYPTO_ALG_TYPE_CIPHER		0x00000001
#define CRYPTO_ALG_TYPE_AEAD		0x00000003
#define CRYPTO_ALG_TYPE_BLKCIPHER	0x00000004
#define CRYPTO_ALG_TYPE_ABLKCIPHER	0x00000005
#define CRYPTO_ALG_TYPE_SKCIPHER	0x00000005
#define CRYPTO_ALG_TYPE_GIVCIPHER	0x00000006
#define CRYPTO_ALG_TYPE_KPP		0x00000008
#define CRYPTO_ALG_TYPE_RNG		0x0000000c
#define CRYPTO_ALG_TYPE_AKCIPHER	0x0000000d
#define CRYPTO_ALG_TYPE_DIGEST		0x0000000e
#define CRYPTO_ALG_TYPE_HASH		0x0000000e
#define CRYPTO_ALG_TYPE_SHASH		0x0000000e
#define CRYPTO_ALG_TYPE_AHASH		0x0000000f

#define CRYPTO_ALG_TYPE_HASH_MASK	0x0000000e
#define CRYPTO_ALG_TYPE_AHASH_MASK	0x0000000e
#define CRYPTO_ALG_TYPE_BLKCIPHER_MASK	0x0000000c

#define CRYPTO_ALG_ASYNC		0x00000080

/*
 * Set this bit if and only if the algorithm requires another algorithm of
 * the same type to handle corner cases.
 */
#define CRYPTO_ALG_NEED_FALLBACK	0x00000100

/*
 * This bit is set for symmetric key ciphers that have already been wrapped
 * with a generic IV generator to prevent them from being wrapped again.
 */
#define CRYPTO_ALG_GENIV		0x00000200

/*
 * Set if the algorithm is an instance that is build from templates.
 */
#define CRYPTO_ALG_INSTANCE		0x00000800

/* Set this bit if the algorithm provided is hardware accelerated but
 * not available to userspace via instruction set or so.
 */
#define CRYPTO_ALG_KERN_DRIVER_ONLY	0x00001000

/*
 * Mark a cipher as a service implementation only usable by another
 * cipher and never by a normal user of the kernel crypto API
 */
#define CRYPTO_ALG_INTERNAL		0x00002000

/*
 * Transform masks and values (for crt_flags).
 */
#define CRYPTO_TFM_REQ_MASK		0x000fff00
#define CRYPTO_TFM_RES_MASK		0xfff00000

#define CRYPTO_TFM_REQ_WEAK_KEY		0x00000100
#define CRYPTO_TFM_REQ_MAY_SLEEP	0x00000200
#define CRYPTO_TFM_REQ_MAY_BACKLOG	0x00000400
#define CRYPTO_TFM_RES_WEAK_KEY		0x00100000
#define CRYPTO_TFM_RES_BAD_KEY_LEN	0x00200000
#define CRYPTO_TFM_RES_BAD_KEY_SCHED	0x00400000
#define CRYPTO_TFM_RES_BAD_BLOCK_LEN	0x00800000
#define CRYPTO_TFM_RES_BAD_FLAGS	0x01000000

/*
 * Miscellaneous stuff.
 */
#define CRYPTO_MAX_ALG_NAME		64

/*
 * The macro CRYPTO_MINALIGN_ATTR (along with the void * type in the actual
 * declaration) is used to ensure that the crypto_tfm context structure is
 * aligned correctly for the given architecture so that there are no alignment
 * faults for C data types.  In particular, this is required on platforms such
 * as arm where pointers are 32-bit aligned but there are data types such as
 * u64 which require 64-bit alignment.
 */
#define CRYPTO_MINALIGN ARCH_KMALLOC_MINALIGN

#define CRYPTO_MINALIGN_ATTR __attribute__ ((__aligned__(CRYPTO_MINALIGN)))

struct scatterlist;
struct crypto_blkcipher;
struct crypto_tfm;
struct crypto_type;
struct skcipher_givcrypt_request;

struct blkcipher_desc {
	struct crypto_blkcipher *tfm;
	void *info;
	u32 flags;
};

struct cipher_desc {
	struct crypto_tfm *tfm;
	void (*crfn)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
	unsigned int (*prfn)(const struct cipher_desc *desc, u8 *dst,
			     const u8 *src, unsigned int nbytes);
	void *info;
};

struct blkcipher_alg {
	int (*setkey)(struct crypto_tfm *tfm, const u8 *key,
	              unsigned int keylen);
	int (*encrypt)(struct blkcipher_desc *desc,
		       struct scatterlist *dst, struct scatterlist *src,
		       unsigned int nbytes);
	int (*decrypt)(struct blkcipher_desc *desc,
		       struct scatterlist *dst, struct scatterlist *src,
		       unsigned int nbytes);

	const char *geniv;

	unsigned int min_keysize;
	unsigned int max_keysize;
	unsigned int ivsize;
};

struct cipher_alg {
	unsigned int cia_min_keysize;
	unsigned int cia_max_keysize;
	int (*cia_setkey)(struct crypto_tfm *tfm, const u8 *key,
	                  unsigned int keylen);
	void (*cia_encrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
	void (*cia_decrypt)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
};

struct compress_alg {
	int (*coa_compress)(struct crypto_tfm *tfm, const u8 *src,
			    unsigned int slen, u8 *dst, unsigned int *dlen);
	int (*coa_decompress)(struct crypto_tfm *tfm, const u8 *src,
			      unsigned int slen, u8 *dst, unsigned int *dlen);
};


#define cra_blkcipher	cra_u.blkcipher
#define cra_cipher	cra_u.cipher
#define cra_compress	cra_u.compress

struct crypto_alg {
	struct list_head cra_list;
	struct list_head cra_users;

	u32 cra_flags;
	unsigned int cra_blocksize;
	unsigned int cra_ctxsize;
	unsigned int cra_alignmask;

	int cra_priority;
	atomic_t cra_refcnt;

	char cra_name[CRYPTO_MAX_ALG_NAME];
	char cra_driver_name[CRYPTO_MAX_ALG_NAME];

	const struct crypto_type *cra_type;

	union {
		struct blkcipher_alg blkcipher;
		struct cipher_alg cipher;
		struct compress_alg compress;
	} cra_u;

	int (*cra_init)(struct crypto_tfm *tfm);
	void (*cra_exit)(struct crypto_tfm *tfm);
	void (*cra_destroy)(struct crypto_alg *alg);

	struct module *cra_module;
} CRYPTO_MINALIGN_ATTR;

/*
 * Algorithm registration interface.
 */
int crypto_register_alg(struct crypto_alg *alg);
int crypto_unregister_alg(struct crypto_alg *alg);
int crypto_register_algs(struct crypto_alg *algs, int count);
int crypto_unregister_algs(struct crypto_alg *algs, int count);

/*
 * Algorithm query interface.
 */
int crypto_has_alg(const char *name, u32 type, u32 mask);

/*
 * Transforms: user-instantiated objects which encapsulate algorithms
 * and core processing logic.  Managed via crypto_alloc_*() and
 * crypto_free_*(), as well as the various helpers below.
 */

struct blkcipher_tfm {
	void *iv;
	int (*setkey)(struct crypto_tfm *tfm, const u8 *key,
		      unsigned int keylen);
	int (*encrypt)(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes);
	int (*decrypt)(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes);
};

struct cipher_tfm {
	int (*cit_setkey)(struct crypto_tfm *tfm,
	                  const u8 *key, unsigned int keylen);
	void (*cit_encrypt_one)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
	void (*cit_decrypt_one)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
};

struct compress_tfm {
	int (*cot_compress)(struct crypto_tfm *tfm,
	                    const u8 *src, unsigned int slen,
	                    u8 *dst, unsigned int *dlen);
	int (*cot_decompress)(struct crypto_tfm *tfm,
	                      const u8 *src, unsigned int slen,
	                      u8 *dst, unsigned int *dlen);
};

#define crt_blkcipher	crt_u.blkcipher
#define crt_cipher	crt_u.cipher
#define crt_compress	crt_u.compress

struct crypto_tfm {

	u32 crt_flags;

	union {
		struct blkcipher_tfm blkcipher;
		struct cipher_tfm cipher;
		struct compress_tfm compress;
	} crt_u;

	void (*exit)(struct crypto_tfm *tfm);

	struct crypto_alg *__crt_alg;

	void *__crt_ctx[] CRYPTO_MINALIGN_ATTR;
};

struct crypto_blkcipher {
	struct crypto_tfm base;
};

struct crypto_cipher {
	struct crypto_tfm base;
};

struct crypto_comp {
	struct crypto_tfm base;
};

enum {
	CRYPTOA_UNSPEC,
	CRYPTOA_ALG,
	CRYPTOA_TYPE,
	CRYPTOA_U32,
	__CRYPTOA_MAX,
};

#define CRYPTOA_MAX (__CRYPTOA_MAX - 1)

/* Maximum number of (rtattr) parameters for each template. */
#define CRYPTO_MAX_ATTRS 32

struct crypto_attr_alg {
	char name[CRYPTO_MAX_ALG_NAME];
};

struct crypto_attr_type {
	u32 type;
	u32 mask;
};

struct crypto_attr_u32 {
	u32 num;
};

/* 
 * Transform user interface.
 */

struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask);
void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm);

static inline void crypto_free_tfm(struct crypto_tfm *tfm)
{
	return crypto_destroy_tfm(tfm, tfm);
}

int alg_test(const char *driver, const char *alg, u32 type, u32 mask);

/*
 * Transform helpers which query the underlying algorithm.
 */
static inline const char *crypto_tfm_alg_name(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_name;
}

static inline const char *crypto_tfm_alg_driver_name(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_driver_name;
}

static inline int crypto_tfm_alg_priority(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_priority;
}

static inline u32 crypto_tfm_alg_type(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_flags & CRYPTO_ALG_TYPE_MASK;
}

static inline unsigned int crypto_tfm_alg_blocksize(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_blocksize;
}

static inline unsigned int crypto_tfm_alg_alignmask(struct crypto_tfm *tfm)
{
	return tfm->__crt_alg->cra_alignmask;
}

static inline u32 crypto_tfm_get_flags(struct crypto_tfm *tfm)
{
	return tfm->crt_flags;
}

static inline void crypto_tfm_set_flags(struct crypto_tfm *tfm, u32 flags)
{
	tfm->crt_flags |= flags;
}

static inline void crypto_tfm_clear_flags(struct crypto_tfm *tfm, u32 flags)
{
	tfm->crt_flags &= ~flags;
}

static inline void *crypto_tfm_ctx(struct crypto_tfm *tfm)
{
	return tfm->__crt_ctx;
}

static inline unsigned int crypto_tfm_ctx_alignment(void)
{
	struct crypto_tfm *tfm;
	return __alignof__(tfm->__crt_ctx);
}

static inline u32 crypto_skcipher_type(u32 type)
{
	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
	type |= CRYPTO_ALG_TYPE_BLKCIPHER;
	return type;
}

static inline u32 crypto_skcipher_mask(u32 mask)
{
	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
	mask |= CRYPTO_ALG_TYPE_BLKCIPHER_MASK;
	return mask;
}

/**
 * DOC: Synchronous Block Cipher API
 *
 * The synchronous block cipher API is used with the ciphers of type
 * CRYPTO_ALG_TYPE_BLKCIPHER (listed as type "blkcipher" in /proc/crypto)
 *
 * Synchronous calls, have a context in the tfm. But since a single tfm can be
 * used in multiple calls and in parallel, this info should not be changeable
 * (unless a lock is used). This applies, for example, to the symmetric key.
 * However, the IV is changeable, so there is an iv field in blkcipher_tfm
 * structure for synchronous blkcipher api. So, its the only state info that can
 * be kept for synchronous calls without using a big lock across a tfm.
 *
 * The block cipher API allows the use of a complete cipher, i.e. a cipher
 * consisting of a template (a block chaining mode) and a single block cipher
 * primitive (e.g. AES).
 *
 * The plaintext data buffer and the ciphertext data buffer are pointed to
 * by using scatter/gather lists. The cipher operation is performed
 * on all segments of the provided scatter/gather lists.
 *
 * The kernel crypto API supports a cipher operation "in-place" which means that
 * the caller may provide the same scatter/gather list for the plaintext and
 * cipher text. After the completion of the cipher operation, the plaintext
 * data is replaced with the ciphertext data in case of an encryption and vice
 * versa for a decryption. The caller must ensure that the scatter/gather lists
 * for the output data point to sufficiently large buffers, i.e. multiples of
 * the block size of the cipher.
 */

static inline struct crypto_blkcipher *__crypto_blkcipher_cast(
	struct crypto_tfm *tfm)
{
	return (struct crypto_blkcipher *)tfm;
}

static inline struct crypto_blkcipher *crypto_blkcipher_cast(
	struct crypto_tfm *tfm)
{
	BUG_ON(crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_BLKCIPHER);
	return __crypto_blkcipher_cast(tfm);
}

/**
 * crypto_alloc_blkcipher() - allocate synchronous block cipher handle
 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
 *	      blkcipher cipher
 * @type: specifies the type of the cipher
 * @mask: specifies the mask for the cipher
 *
 * Allocate a cipher handle for a block cipher. The returned struct
 * crypto_blkcipher is the cipher handle that is required for any subsequent
 * API invocation for that block cipher.
 *
 * Return: allocated cipher handle in case of success; IS_ERR() is true in case
 *	   of an error, PTR_ERR() returns the error code.
 */
static inline struct crypto_blkcipher *crypto_alloc_blkcipher(
	const char *alg_name, u32 type, u32 mask)
{
	type &= ~CRYPTO_ALG_TYPE_MASK;
	type |= CRYPTO_ALG_TYPE_BLKCIPHER;
	mask |= CRYPTO_ALG_TYPE_MASK;

	return __crypto_blkcipher_cast(crypto_alloc_base(alg_name, type, mask));
}

static inline struct crypto_tfm *crypto_blkcipher_tfm(
	struct crypto_blkcipher *tfm)
{
	return &tfm->base;
}

/**
 * crypto_free_blkcipher() - zeroize and free the block cipher handle
 * @tfm: cipher handle to be freed
 */
static inline void crypto_free_blkcipher(struct crypto_blkcipher *tfm)
{
	crypto_free_tfm(crypto_blkcipher_tfm(tfm));
}

/**
 * crypto_has_blkcipher() - Search for the availability of a block cipher
 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
 *	      block cipher
 * @type: specifies the type of the cipher
 * @mask: specifies the mask for the cipher
 *
 * Return: true when the block cipher is known to the kernel crypto API; false
 *	   otherwise
 */
static inline int crypto_has_blkcipher(const char *alg_name, u32 type, u32 mask)
{
	type &= ~CRYPTO_ALG_TYPE_MASK;
	type |= CRYPTO_ALG_TYPE_BLKCIPHER;
	mask |= CRYPTO_ALG_TYPE_MASK;

	return crypto_has_alg(alg_name, type, mask);
}

/**
 * crypto_blkcipher_name() - return the name / cra_name from the cipher handle
 * @tfm: cipher handle
 *
 * Return: The character string holding the name of the cipher
 */
static inline const char *crypto_blkcipher_name(struct crypto_blkcipher *tfm)
{
	return crypto_tfm_alg_name(crypto_blkcipher_tfm(tfm));
}

static inline struct blkcipher_tfm *crypto_blkcipher_crt(
	struct crypto_blkcipher *tfm)
{
	return &crypto_blkcipher_tfm(tfm)->crt_blkcipher;
}

static inline struct blkcipher_alg *crypto_blkcipher_alg(
	struct crypto_blkcipher *tfm)
{
	return &crypto_blkcipher_tfm(tfm)->__crt_alg->cra_blkcipher;
}

/**
 * crypto_blkcipher_ivsize() - obtain IV size
 * @tfm: cipher handle
 *
 * The size of the IV for the block cipher referenced by the cipher handle is
 * returned. This IV size may be zero if the cipher does not need an IV.
 *
 * Return: IV size in bytes
 */
static inline unsigned int crypto_blkcipher_ivsize(struct crypto_blkcipher *tfm)
{
	return crypto_blkcipher_alg(tfm)->ivsize;
}

/**
 * crypto_blkcipher_blocksize() - obtain block size of cipher
 * @tfm: cipher handle
 *
 * The block size for the block cipher referenced with the cipher handle is
 * returned. The caller may use that information to allocate appropriate
 * memory for the data returned by the encryption or decryption operation.
 *
 * Return: block size of cipher
 */
static inline unsigned int crypto_blkcipher_blocksize(
	struct crypto_blkcipher *tfm)
{
	return crypto_tfm_alg_blocksize(crypto_blkcipher_tfm(tfm));
}

static inline unsigned int crypto_blkcipher_alignmask(
	struct crypto_blkcipher *tfm)
{
	return crypto_tfm_alg_alignmask(crypto_blkcipher_tfm(tfm));
}

static inline u32 crypto_blkcipher_get_flags(struct crypto_blkcipher *tfm)
{
	return crypto_tfm_get_flags(crypto_blkcipher_tfm(tfm));
}

static inline void crypto_blkcipher_set_flags(struct crypto_blkcipher *tfm,
					      u32 flags)
{
	crypto_tfm_set_flags(crypto_blkcipher_tfm(tfm), flags);
}

static inline void crypto_blkcipher_clear_flags(struct crypto_blkcipher *tfm,
						u32 flags)
{
	crypto_tfm_clear_flags(crypto_blkcipher_tfm(tfm), flags);
}

/**
 * crypto_blkcipher_setkey() - set key for cipher
 * @tfm: cipher handle
 * @key: buffer holding the key
 * @keylen: length of the key in bytes
 *
 * The caller provided key is set for the block cipher referenced by the cipher
 * handle.
 *
 * Note, the key length determines the cipher type. Many block ciphers implement
 * different cipher modes depending on the key size, such as AES-128 vs AES-192
 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
 * is performed.
 *
 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
 */
static inline int crypto_blkcipher_setkey(struct crypto_blkcipher *tfm,
					  const u8 *key, unsigned int keylen)
{
	return crypto_blkcipher_crt(tfm)->setkey(crypto_blkcipher_tfm(tfm),
						 key, keylen);
}

/**
 * crypto_blkcipher_encrypt() - encrypt plaintext
 * @desc: reference to the block cipher handle with meta data
 * @dst: scatter/gather list that is filled by the cipher operation with the
 *	ciphertext
 * @src: scatter/gather list that holds the plaintext
 * @nbytes: number of bytes of the plaintext to encrypt.
 *
 * Encrypt plaintext data using the IV set by the caller with a preceding
 * call of crypto_blkcipher_set_iv.
 *
 * The blkcipher_desc data structure must be filled by the caller and can
 * reside on the stack. The caller must fill desc as follows: desc.tfm is filled
 * with the block cipher handle; desc.flags is filled with either
 * CRYPTO_TFM_REQ_MAY_SLEEP or 0.
 *
 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
 */
static inline int crypto_blkcipher_encrypt(struct blkcipher_desc *desc,
					   struct scatterlist *dst,
					   struct scatterlist *src,
					   unsigned int nbytes)
{
	desc->info = crypto_blkcipher_crt(desc->tfm)->iv;
	return crypto_blkcipher_crt(desc->tfm)->encrypt(desc, dst, src, nbytes);
}

/**
 * crypto_blkcipher_encrypt_iv() - encrypt plaintext with dedicated IV
 * @desc: reference to the block cipher handle with meta data
 * @dst: scatter/gather list that is filled by the cipher operation with the
 *	ciphertext
 * @src: scatter/gather list that holds the plaintext
 * @nbytes: number of bytes of the plaintext to encrypt.
 *
 * Encrypt plaintext data with the use of an IV that is solely used for this
 * cipher operation. Any previously set IV is not used.
 *
 * The blkcipher_desc data structure must be filled by the caller and can
 * reside on the stack. The caller must fill desc as follows: desc.tfm is filled
 * with the block cipher handle; desc.info is filled with the IV to be used for
 * the current operation; desc.flags is filled with either
 * CRYPTO_TFM_REQ_MAY_SLEEP or 0.
 *
 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
 */
static inline int crypto_blkcipher_encrypt_iv(struct blkcipher_desc *desc,
					      struct scatterlist *dst,
					      struct scatterlist *src,
					      unsigned int nbytes)
{
	return crypto_blkcipher_crt(desc->tfm)->encrypt(desc, dst, src, nbytes);
}

/**
 * crypto_blkcipher_decrypt() - decrypt ciphertext
 * @desc: reference to the block cipher handle with meta data
 * @dst: scatter/gather list that is filled by the cipher operation with the
 *	plaintext
 * @src: scatter/gather list that holds the ciphertext
 * @nbytes: number of bytes of the ciphertext to decrypt.
 *
 * Decrypt ciphertext data using the IV set by the caller with a preceding
 * call of crypto_blkcipher_set_iv.
 *
 * The blkcipher_desc data structure must be filled by the caller as documented
 * for the crypto_blkcipher_encrypt call above.
 *
 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
 *
 */
static inline int crypto_blkcipher_decrypt(struct blkcipher_desc *desc,
					   struct scatterlist *dst,
					   struct scatterlist *src,
					   unsigned int nbytes)
{
	desc->info = crypto_blkcipher_crt(desc->tfm)->iv;
	return crypto_blkcipher_crt(desc->tfm)->decrypt(desc, dst, src, nbytes);
}

/**
 * crypto_blkcipher_decrypt_iv() - decrypt ciphertext with dedicated IV
 * @desc: reference to the block cipher handle with meta data
 * @dst: scatter/gather list that is filled by the cipher operation with the
 *	plaintext
 * @src: scatter/gather list that holds the ciphertext
 * @nbytes: number of bytes of the ciphertext to decrypt.
 *
 * Decrypt ciphertext data with the use of an IV that is solely used for this
 * cipher operation. Any previously set IV is not used.
 *
 * The blkcipher_desc data structure must be filled by the caller as documented
 * for the crypto_blkcipher_encrypt_iv call above.
 *
 * Return: 0 if the cipher operation was successful; < 0 if an error occurred
 */
static inline int crypto_blkcipher_decrypt_iv(struct blkcipher_desc *desc,
					      struct scatterlist *dst,
					      struct scatterlist *src,
					      unsigned int nbytes)
{
	return crypto_blkcipher_crt(desc->tfm)->decrypt(desc, dst, src, nbytes);
}

/**
 * crypto_blkcipher_set_iv() - set IV for cipher
 * @tfm: cipher handle
 * @src: buffer holding the IV
 * @len: length of the IV in bytes
 *
 * The caller provided IV is set for the block cipher referenced by the cipher
 * handle.
 */
static inline void crypto_blkcipher_set_iv(struct crypto_blkcipher *tfm,
					   const u8 *src, unsigned int len)
{
	memcpy(crypto_blkcipher_crt(tfm)->iv, src, len);
}

/**
 * crypto_blkcipher_get_iv() - obtain IV from cipher
 * @tfm: cipher handle
 * @dst: buffer filled with the IV
 * @len: length of the buffer dst
 *
 * The caller can obtain the IV set for the block cipher referenced by the
 * cipher handle and store it into the user-provided buffer. If the buffer
 * has an insufficient space, the IV is truncated to fit the buffer.
 */
static inline void crypto_blkcipher_get_iv(struct crypto_blkcipher *tfm,
					   u8 *dst, unsigned int len)
{
	memcpy(dst, crypto_blkcipher_crt(tfm)->iv, len);
}

/**
 * DOC: Single Block Cipher API
 *
 * The single block cipher API is used with the ciphers of type
 * CRYPTO_ALG_TYPE_CIPHER (listed as type "cipher" in /proc/crypto).
 *
 * Using the single block cipher API calls, operations with the basic cipher
 * primitive can be implemented. These cipher primitives exclude any block
 * chaining operations including IV handling.
 *
 * The purpose of this single block cipher API is to support the implementation
 * of templates or other concepts that only need to perform the cipher operation
 * on one block at a time. Templates invoke the underlying cipher primitive
 * block-wise and process either the input or the output data of these cipher
 * operations.
 */

static inline struct crypto_cipher *__crypto_cipher_cast(struct crypto_tfm *tfm)
{
	return (struct crypto_cipher *)tfm;
}

static inline struct crypto_cipher *crypto_cipher_cast(struct crypto_tfm *tfm)
{
	BUG_ON(crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_CIPHER);
	return __crypto_cipher_cast(tfm);
}

/**
 * crypto_alloc_cipher() - allocate single block cipher handle
 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
 *	     single block cipher
 * @type: specifies the type of the cipher
 * @mask: specifies the mask for the cipher
 *
 * Allocate a cipher handle for a single block cipher. The returned struct
 * crypto_cipher is the cipher handle that is required for any subsequent API
 * invocation for that single block cipher.
 *
 * Return: allocated cipher handle in case of success; IS_ERR() is true in case
 *	   of an error, PTR_ERR() returns the error code.
 */
static inline struct crypto_cipher *crypto_alloc_cipher(const char *alg_name,
							u32 type, u32 mask)
{
	type &= ~CRYPTO_ALG_TYPE_MASK;
	type |= CRYPTO_ALG_TYPE_CIPHER;
	mask |= CRYPTO_ALG_TYPE_MASK;

	return __crypto_cipher_cast(crypto_alloc_base(alg_name, type, mask));
}

static inline struct crypto_tfm *crypto_cipher_tfm(struct crypto_cipher *tfm)
{
	return &tfm->base;
}

/**
 * crypto_free_cipher() - zeroize and free the single block cipher handle
 * @tfm: cipher handle to be freed
 */
static inline void crypto_free_cipher(struct crypto_cipher *tfm)
{
	crypto_free_tfm(crypto_cipher_tfm(tfm));
}

/**
 * crypto_has_cipher() - Search for the availability of a single block cipher
 * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
 *	     single block cipher
 * @type: specifies the type of the cipher
 * @mask: specifies the mask for the cipher
 *
 * Return: true when the single block cipher is known to the kernel crypto API;
 *	   false otherwise
 */
static inline int crypto_has_cipher(const char *alg_name, u32 type, u32 mask)
{
	type &= ~CRYPTO_ALG_TYPE_MASK;
	type |= CRYPTO_ALG_TYPE_CIPHER;
	mask |= CRYPTO_ALG_TYPE_MASK;

	return crypto_has_alg(alg_name, type, mask);
}

static inline struct cipher_tfm *crypto_cipher_crt(struct crypto_cipher *tfm)
{
	return &crypto_cipher_tfm(tfm)->crt_cipher;
}

/**
 * crypto_cipher_blocksize() - obtain block size for cipher
 * @tfm: cipher handle
 *
 * The block size for the single block cipher referenced with the cipher handle
 * tfm is returned. The caller may use that information to allocate appropriate
 * memory for the data returned by the encryption or decryption operation
 *
 * Return: block size of cipher
 */
static inline unsigned int crypto_cipher_blocksize(struct crypto_cipher *tfm)
{
	return crypto_tfm_alg_blocksize(crypto_cipher_tfm(tfm));
}

static inline unsigned int crypto_cipher_alignmask(struct crypto_cipher *tfm)
{
	return crypto_tfm_alg_alignmask(crypto_cipher_tfm(tfm));
}

static inline u32 crypto_cipher_get_flags(struct crypto_cipher *tfm)
{
	return crypto_tfm_get_flags(crypto_cipher_tfm(tfm));
}

static inline void crypto_cipher_set_flags(struct crypto_cipher *tfm,
					   u32 flags)
{
	crypto_tfm_set_flags(crypto_cipher_tfm(tfm), flags);
}

static inline void crypto_cipher_clear_flags(struct crypto_cipher *tfm,
					     u32 flags)
{
	crypto_tfm_clear_flags(crypto_cipher_tfm(tfm), flags);
}

/**
 * crypto_cipher_setkey() - set key for cipher
 * @tfm: cipher handle
 * @key: buffer holding the key
 * @keylen: length of the key in bytes
 *
 * The caller provided key is set for the single block cipher referenced by the
 * cipher handle.
 *
 * Note, the key length determines the cipher type. Many block ciphers implement
 * different cipher modes depending on the key size, such as AES-128 vs AES-192
 * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128
 * is performed.
 *
 * Return: 0 if the setting of the key was successful; < 0 if an error occurred
 */
static inline int crypto_cipher_setkey(struct crypto_cipher *tfm,
                                       const u8 *key, unsigned int keylen)
{
	return crypto_cipher_crt(tfm)->cit_setkey(crypto_cipher_tfm(tfm),
						  key, keylen);
}

/**
 * crypto_cipher_encrypt_one() - encrypt one block of plaintext
 * @tfm: cipher handle
 * @dst: points to the buffer that will be filled with the ciphertext
 * @src: buffer holding the plaintext to be encrypted
 *
 * Invoke the encryption operation of one block. The caller must ensure that
 * the plaintext and ciphertext buffers are at least one block in size.
 */
static inline void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
					     u8 *dst, const u8 *src)
{
	crypto_cipher_crt(tfm)->cit_encrypt_one(crypto_cipher_tfm(tfm),
						dst, src);
}

/**
 * crypto_cipher_decrypt_one() - decrypt one block of ciphertext
 * @tfm: cipher handle
 * @dst: points to the buffer that will be filled with the plaintext
 * @src: buffer holding the ciphertext to be decrypted
 *
 * Invoke the decryption operation of one block. The caller must ensure that
 * the plaintext and ciphertext buffers are at least one block in size.
 */
static inline void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
					     u8 *dst, const u8 *src)
{
	crypto_cipher_crt(tfm)->cit_decrypt_one(crypto_cipher_tfm(tfm),
						dst, src);
}

#endif	/* _LINUX_CRYPTO_H */